J.C. Penney Co. Chief Executive Myron “Mike” Ullman bought 112 ,000 shares of his company stock last week at about $8.95 a share, according to a regulatory filing.

The disclosed buying activity comes at a time when J.C. Penney’s share price has notched steep losses this year. The struggling department-store chain will be kicked out of the S&P 500 on Friday after the close of trading, S&P Dow Jones Indices announced last week, due to its dwindling market value.

Mr. Ullman’s purchase amounts to a little more than $1 million.

J.C. Penney shares rose 2.8% in late trading to $9.45. The stock has lost more than half its value this year through Monday’s close, although it has rebounded 40% since the end of last month.

Mr. Ullman retook the top job at J.C. Penney in April, succeeding former Apple executive Ron Johnson, whose failed attempt to remake Penney by doing away with promotions and eliminating in-house brands resulted in a $1 billion loss and a 25% drop in sales during his first year on the job.

To win customers back, Mr. Ullman has reverted to heavy discounting that has helped sales but has taken a toll on margins. Last week J.C. Penney reported its fiscal third-quarter loss widened from a year ago as sales weakened. But the company acknowledged that margins improved each month throughout the third quarter.

In October, J.C. Penney notched its first monthly same-store sales growth since December 2011.